Delhi experienced the most intense fog of the season, causing disruptions in transportation, with over 25 trains and approximately 50 flights facing delays on Wednesday morning. The visibility dropped to 50 meters in Safdarjung and Palam, and air quality was expected to deteriorate into the severe zone later in the day.
According to a spokesperson for Northern Railways, at least 25 trains were delayed by more than an hour, with the Puri-New Delhi Purushottam Express and the Howrah-New Delhi Poorvah Express running more than five hours behind schedule. The reduced speeds of trains during dense fog in winter aim to prevent mishaps.
Up until 9 a.m., there were no reports of flight diversions, but around 50 flights experienced delays, categorized as such when they were over 15 minutes late.
An official from the India Meteorological Department (IMD) noted that the fog on Wednesday was the thickest, intensifying across northern India and lasting longer than the previous day. Visibility dropped to 50 meters in various cities, including Amritsar, Lucknow, and Agra.
The IMD classifies fog as shallow, moderate, dense, or very dense based on visibility levels, with the latter being 50 meters or lower.
At 9 a.m. on Wednesday, Delhi recorded an average Air Quality Index (AQI) of 380 (very poor), compared to 377 (very poor) at 4 p.m. the previous day. The mercury dipped to 7°C. The air quality was expected to remain in the severe category until Friday, with the subsequent six days fluctuating between very poor and severe zones.
After three consecutive days in the severe zone, the AQI improved on Monday but still remained significantly above safe limits. The daytime temperatures, reaching up to 22°C, have been attributed to the El Nino weather phenomenon, providing some relief from the colder nights.